Claude Opus 5 vs. Claude Fable 5 (2026): Half the Price, Half a Percent Off the Peak
Claude Opus 5 vs Claude Fable 5 in 2026: list price, cost per completed task, knowledge cutoff, caching and where Fable still holds the peak.
Opus 5 is the right default for almost everyone, and the argument is not that it is the smarter model — it is that it removes the reason to pay double. Half the list price, half the cache-hit price, a lower cache minimum, a four-month fresher knowledge cutoff and a faster latency rating are not marginal gains that need a benchmark to justify them; they show up on the invoice and in agent runtime whether or not the leaderboard moves. On Anthropic's own task-level numbers the cost story is stronger still: half the cost per task on CursorBench 3.2 for a score within 0.5% of Fable 5's peak, and a third of the cost on OSWorld 2.0 for a better result. What Fable 5 keeps is narrow but real. It still holds the peak on the benchmark Anthropic used to make the cost argument, the Mythos class remains ahead on cybersecurity evaluations, and it has a public record where Opus 5 has a launch post. That last point deserves more weight than it usually gets: at the time of writing, the numbers that make Opus 5 look dominant are Anthropic's own charts, published two days ago, and the one third-party leaderboard we checked labels its #1 placement "Estimated" while Fable 5's lower placement is "Supported". That is not evidence that the claims are wrong — it is a reason to verify them on your own workload before you re-platform a production pipeline. The practical decision splits cleanly. If you are on Opus 4.8, move: it is the same price and a strictly better model by every published measure, so the only work is re-checking max_tokens now that thinking is on by default. If you are on Fable 5, run one honest evaluation before switching — if Opus 5 holds on your tasks, you halve a recurring bill; if your workload lives in the last half percent, you have just paid for the evidence that Fable 5 is worth its price. And if you were about to pay Fable rates purely for speed, note that Opus 5's Fast mode costs exactly the same $10 / $50, which makes that a direct comparison rather than a tier decision.
Detailed Comparison
A side-by-side analysis of key factors to help you make the right choice.
| Factor | The new defaultRecommended | The frontier ceiling | Winner |
|---|---|---|---|
| List API price | $5 per million input tokens, $25 per million output tokens. | $10 per million input tokens, $50 per million output tokens — exactly double. | |
| Cost per completed task | On CursorBench 3.2 at max effort it lands within 0.5% of Fable 5's peak score at half the cost per task; on OSWorld 2.0 it beats Fable 5's best result at just over a third of the cost. | Holds the peak score on those same benchmarks, but pays roughly two to three times as much per completed task to get there. | |
| Ceiling on the hardest tasks | Anthropic's own wording is "comes close to" the frontier — near-frontier, by the vendor's own description. | Still the top of the Claude range, and the Mythos class remains ahead of Opus 5 on cybersecurity evaluations. | |
| Knowledge freshness | Reliable knowledge cutoff May 2026. | Reliable knowledge cutoff January 2026 — four months older. | |
| Caching economics | Cache hits and refreshes at $0.50 per million tokens, and the minimum cacheable prompt drops to 512 tokens. | Cache hits and refreshes at $1 per million tokens, with the usual 1,024-token minimum. | |
| Latency profile | Rated "moderate" on Anthropic's comparative-latency scale. | Rated "slower" — the price of the extra ceiling. | |
| Context window and output limit | 1M-token context window (both the default and the maximum, no smaller variant) and 128k maximum output. | 1M-token context window and 128k maximum output — identical. | |
| Strength of the evidence | Two days old at the time of writing: the headline numbers are Anthropic's own charts, and BenchLM lists its #1 placement with an "Estimated" evidence label. | Generally available since June 2026, with a public track record; BenchLM lists its #3 placement as "Supported". | |
| Total Score | 5/ 8 | 2/ 8 | 1 ties |
Key Statistics
Real data from verified industry sources to support your decision.
Claude Platform Docs — Pricing
Anthropic — Introducing Claude Opus 5
Anthropic — Introducing Claude Opus 5
Anthropic — Introducing Claude Opus 5
Claude Platform Docs — Models overview
BenchLM
All statistics come from verified third-party sources. Source, year, and direct link are shown on each metric.
When to Choose Each Option
Clear guidance based on your specific situation and needs.
Choose The new default when...
- You run high-volume agentic or coding work where the cost per completed task decides the budget, not the top of a leaderboard.
- Your agents lean on prompt caching: the $0.50 cache-hit rate and the 512-token cache minimum compound across long sessions.
- Your workload touches anything between January and May 2026 and you would otherwise pay for retrieval to close that gap.
- You are already on Opus 4.8 — Opus 5 costs the same, so the upgrade is an evaluation question, not a budget request.
Choose The frontier ceiling when...
- You need the highest available score on the hardest tasks and the last half percent is worth paying double for.
- Your evaluation policy requires a public track record: Fable 5 has been generally available since June 2026, Opus 5 for days.
- Your work is security-heavy — the Mythos class remains ahead of Opus 5 on cybersecurity evaluations.
- Your pipeline is tuned and validated against Fable 5's behaviour and a full re-evaluation would cost more than the price difference saves.
Our Recommendation
Opus 5 is the right default for almost everyone, and the argument is not that it is the smarter model — it is that it removes the reason to pay double. Half the list price, half the cache-hit price, a lower cache minimum, a four-month fresher knowledge cutoff and a faster latency rating are not marginal gains that need a benchmark to justify them; they show up on the invoice and in agent runtime whether or not the leaderboard moves. On Anthropic's own task-level numbers the cost story is stronger still: half the cost per task on CursorBench 3.2 for a score within 0.5% of Fable 5's peak, and a third of the cost on OSWorld 2.0 for a better result. What Fable 5 keeps is narrow but real. It still holds the peak on the benchmark Anthropic used to make the cost argument, the Mythos class remains ahead on cybersecurity evaluations, and it has a public record where Opus 5 has a launch post. That last point deserves more weight than it usually gets: at the time of writing, the numbers that make Opus 5 look dominant are Anthropic's own charts, published two days ago, and the one third-party leaderboard we checked labels its #1 placement "Estimated" while Fable 5's lower placement is "Supported". That is not evidence that the claims are wrong — it is a reason to verify them on your own workload before you re-platform a production pipeline. The practical decision splits cleanly. If you are on Opus 4.8, move: it is the same price and a strictly better model by every published measure, so the only work is re-checking max_tokens now that thinking is on by default. If you are on Fable 5, run one honest evaluation before switching — if Opus 5 holds on your tasks, you halve a recurring bill; if your workload lives in the last half percent, you have just paid for the evidence that Fable 5 is worth its price. And if you were about to pay Fable rates purely for speed, note that Opus 5's Fast mode costs exactly the same $10 / $50, which makes that a direct comparison rather than a tier decision.
Frequently Asked Questions
Common questions about this comparison answered.
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